There's something in 20 that says if its fire plus domestic the pump at least is NOT governed by 20. Maybe you don't need a real fire pump, just make the well pumps bigger. The variable speed seems to be work well (lol) over the range of low domestic and high FP. But it sounds like they have some serious domestic concerns so maybe that is the driving force.
On the surface I don't see a problem, just think it through and compare issue to something similar in the standards. IMHO it's not unlike dedicated tanks. What happens if they leak or are not refilled? You might find some information about local variation in the wells. The locals know how the seasons affect the levels. Definitely want a full flow test of the system at demand (maybe including the high domestic) for several hours to make sure the volume lasts as long as expected. I think you need to discuss reliability like physical protection of the wire and UG piping. But nothing more than assumed in 20 or 70-695 for traditional setups. Perhaps backup generators but a traditional FP doesn't normally require backup generators. I also believe in the pump/riser room you need to have some signage to point out the source is not normal. And if no fire pump a means to test to demands annually. And have information so the sprinkler co in the future can easily know when the supply is falling short and the screens in the well need to be checked or the pumps looked at. We've done 2 and I think they came out well (can't help myself), tried a couple other times but the up charge on the well was more than traditional FP and tanks or the well driller in his experience didn't think we'd get those demands. And because it's not covered in NFPA doc, technically an FPE should be involved at some point. Over the years you've proved your competence but don't get in trouble over a technical issue. Chris Cahill, P.E. Fire Protection Engineer Sentry Fire Protection, Inc. 763-658-4483 763-658-4921 fax Email: [email protected] Mail: P.O. Box 69 Waverly, MN 55390 Location: 4439 Hwy 12 SW Waverly, MN 55390 -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of [email protected] Sent: Tuesday, April 13, 2010 3:57 PM To: [email protected] Subject: Wells as a water source We've got a rural chemical processing plant. No real municipal water supply. Owner wants to use wells, 3 at 1500 gpm each with an estimated, pumped residual pressure of approximately 26 psi at the surface. So there will be a pump within the well supplying water to a multi-use water main which will then branch off to feed the fire pumps. It is their desire not to have a fire water tank. Well water supply is supposed to be extremely reliable in this area. At this stage of the game maximum system demand is yet to be determined. The question is what are the issues with having a well pump or pumps serving a fire pump? Any restrictions or things to consider? I have found nothing giving any specific guidelines concerning this arrangement. I've looked at NFPA 20, 2007, 7.2 and NFPA 1142 and it appears that a dedicated fire well is presumed. These wells are going to be costly so they will not want to drill wells dedicated to FP only. Craig L. Prahl, CET Fire Protection Specialist Mechanical Department CH2MHILL Lockwood Greene 1500 International Drive PO Box 491, Spartanburg, SC 29304-0491 Direct - 864.599.4102 Fax - 864.599.8439 [email protected] http://www.ch2m.com _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field) _______________________________________________ Sprinklerforum mailing list [email protected] http://fireball.firesprinkler.org/mailman/listinfo/sprinklerforum For Technical Assistance, send an email to: [email protected] To Unsubscribe, send an email to:[email protected] (Put the word unsubscribe in the subject field)
